APPENDIX. 541 



to believe are the real germs of the future generations of 

 cells. 



" From comparative observations it would appear that the 

 development and growth of fat proceed at different rates in 

 different localities of the same body, it being more advanced 

 in one situation than in another ; and also in the same parts 

 in different children of the same age ; so that an exactly 

 similar condition of things to that which I have described as 

 existing in the masses of fat which occur in the region of the 

 neck in the mature foetus, must not in all cases be looked 

 for. 



" The structural resemblance which I have shown to exist 

 between fat cells in an early condition of their development, 

 and the cells of sebaceous glands is most interesting, the 

 latter appearing to be, in fact, simply fat in a rudimentary 

 and imperfect state of its development." 



On the Structure and Formation of the Nails. 



Since the publication of the article contained in this work 

 on the structure of nail, some further observations by 

 Mr. Rainey, on the same subject, have appeared ; the more 

 important of these are contained in the following ex- 

 tracts * : 



" The object of this paper is to show that the nails consist of at least 

 two distinct structures : one proper to them, the horny structure, and 

 the other the cuticular one ; and also, that their matrix possesses one set 

 of vessels expressly for the secretion of the horny part of the nail, and 

 another set for the formation of the cuticular portion ; and that besides 

 these, there are other vessels differing in their characters and arrange- 

 ment from the preceding, and probably intended to furnish a material, 

 intermediate in some of its properties between horn and cuticle ; and 

 destined to blend these together, and thus to preserve their union 

 during the growth and protrusion of the nails. However far this idea 

 may be correct, the anatomical fact of there being these three different 

 arrangements of vessels is indisputable. 



* On the Structure and Formation of the Nails of the Fingers and 

 Toes. By G. Rainey, Esq., M.R.C.L. Transactions of the Microscopical 

 Society, March, 1849. 



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